Vacuum cleaner



FIG. 1 is a perspective view of the present design for a vacuum cleaner;

FIG. 2 is a front view thereof,

FIG. 3 is a right side view thereof,

FIG. 4 is a left side view thereof,

FIG. 5 is a top view thereof,

FIG. 6 is a rear view thereof; and,

FIG. 7 is a bottom view thereof.

An ornamental design for a vacuum cleaner, substantially as shown.